The invention relates to novel heteroaryl compounds, methods for their preparation, and to a therapeutic process for their use as medicaments, particularly for treating tumors.
According to one aspect of the invention, novel acridine derivatives are provided of the formula (1) 
wherein
R, R1, R2, R3 are attached to any of the acridine carbon atoms C1-9 and are the same or different and independently of one another are hydrogen, hydroxyl, a straight-chain or branched C1-8 alkyl, C3-7 cycloalkyl, straight-chain or branched C1-8 alkylcarbonyl, suitably acetyl, straight-chain or branched C1-8 alkoxy, halogen, aryl-C1-8 alkoxy, suitably benzyloxy or phenylethyloxy, nitro, amino, mono-C1-4 alkylamino, di-C1-4 alkylamino, C1-8 alkoxycarbonylamino, C1-6 alkoxycarbonylamino-C1-8 alkyl, cyano, straight-chain or branched cyano-C1-6 alkyl, carboxyl, C1-8 alkoxycarbonyl, C1-4 alkyl which is substituted by one or more fluorine atoms, suitably the trifluoromethyl group, carboxy-C1-8 alkyl or C1-8 alkoxycarbonyl-C1-6 alkyl, C1-6 alkenyl, suitably allyl, C2-6 alkynyl, suitably ethynyl or propargyl, straight-chain or branched cyano-C1-6 alkyl, suitably cyanomethyl, aryl, where the aryl radical is unsubstituted or mono- or polysubstituted by identical or different substituents from the group of halogen, straight-chain or branched C1-8 alkyl, C3-7 cycloalkyl, carboxyl, straight-chain or branched C1-8 alkoxycarbonyl, suitably tert-butoxycarbonyl, by trifluoromethyl, hydroxyl, straight-chain or branched C1-8 alkoxy, suitably methoxy or ethoxy, benzyloxy, nitro, amino, mono-C1-4 alkylamino, di-C1-4 alkylamino, cyano, straight-chain or branched cyano-C1-6 alkyl,
Z is oxygen or sulfur, where the radical 
substituted on the acridine heterocycle is attached to a C atom C1-9 of the acridine ring skeleton;
P, Q independently of one another represent oxygen or in each case two hydrogen atoms (i.e. xe2x80x94CH2);
X is nitrogen or Cxe2x80x94R5, where R5 is hydrogen or C1-6 alkyl;
n,m independently of one another denotes a cardinal number between 0 and 3, with the proviso that when n=0, X is a CR5R6 group where R5 and R6 independently of one another represent hydrogen or C1-6 alkyl and that the nitrogen atom adjacent to the Cxe2x95x90Z group is substituted by a hydrogen atom or a C1-6 alkyl group;
R4 is a straight-chain or branched C1-20 alkyl radical which can be saturated or unsaturated, with one to three double and/or triple bonds, and which can be unsubstituted or substituted at the same or different C atoms by one, two or more aryl, heteroaryl, halogen, cyano, xe2x80x94Cxe2x95x90NH (NH2), C1-6 alkoxycarbonylamino, C1-6 alkoxy, amino, mono-C1-4 alkylamino or di-C1-4 alkylamino; carboxy, C1-4 alkoxycarbonyl; a C6-14 aryl radical, C6-14 aryl-C1-4 alkyl radical or a C2-10 heteroaryl or C2-10 heteroaryl-C1-4 alkyl radical which contains one or more heteroatoms that are N, O or S, where the C1-4 alkyl radical can be unsubstituted or mono- or polysubstituted with the same or different substituents from the group of C1-6 alkyl, halogen or oxo (xe2x95x90O), and where the C6-14 aryl or C2-10 heteroaryl radical is unsubstituted or mono- or polysubstituted by the same or different substituents from the group of straight-chain or branched C1-8 alkyl, C3-7 cycloalkyl, halogen, cyano, C1-6 alkoxycarbonylamino, C1-6 alkoxy, carboxyl, C1-8 alkoxycarbonyl, straight-chain or branched C1-6 alkyl which is substituted by one or more fluorine atoms, suitably trifluoromethyl, hydroxyl, straight-chain or branched C1-8 alkoxy, suitably methoxy or ethoxy, where adjacent oxygen atoms can also be linked by C1-2 alkylene groups, suitably by a methylene group, benzyloxy, nitro, amino, mono-C1-4 alkylamino, di-C1-4 alkylamino, aryl, which for its part can be unsubstituted or mono- or polysubstituted by identical or different substituents from the group of straight-chain or branched C1-8 alkyl, C3-7 cycloalkyl, carboxyl, straight-chain or branched C1-8 alkoxycarbonyl, by trifluoromethyl, hydroxyl, straight-chain or branched C1-8 alkoxy, suitably methoxy or ethoxy, benzyloxy, nitro, amino, mono-C1-4 alkylamino, di-C1-4 alkylamino, cyano, straight-chain or branched cyano-C1-6 alkyl;
and their structural isomers and stereoisomers, particularly tautomers, diastereomers and enantiomers, and their pharmaceutically acceptable salts, particularly acid addition salts.
Thus, for example, the compounds of the formula (1) of the present invention which have one or more centers of chirality and which are present as racemates and can be separated by methods known per se into their optical isomers, i.e. enantiomers or diastereomers. The separation can be carried out by column separation on chiral phases or by recrystallization from an optically active solvent or using an optically active acid or base or by derivatization with an optically active reagent, such as, for example, an optically active alcohol, and subsequent removal of the radical.
Furthermore, the acridine derivatives of the formula (1) of the present invention can be converted into their salts with inorganic or organic acids, especially for pharmaceutical use, into their pharmaceutically acceptable salts. Acids which are suitable for this purpose are, for example, hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, fumaric acid, succinic acid, lactic acid, citric acid, acetic acid, tartaric acid, malic acid, malonic acid, embonic acid, trifluoroacetic acid maleic acid, methonesulfuric acid, or sulfo acetic acid.
Moreover, the compounds of the formula (1) of the invention if desired can be converted if they contain a sufficiently acidic group, such as a carboxyl group, into their salts with inorganic or organic bases, especially for pharmaceutical use, into their pharmaceutically acceptable salts. Bases which are suitable for this purpose are, for example, sodium hydroxide, potassium hydroxide, calcium hydroxide, lysine, cyclohexylamine, ethanolamine, diethanolamine and triethanolamine.
According to a further embodiment, acridine derivatives of the formula (1) are provided in which R, R1, R2, R3, X, Z, P, Q, n and m have the meanings given above and R4 is phenyl which is unsubstituted or substituted by one or up to five the same or different C1-6 alkoxy groups, in which adjacent oxygen atoms can also be linked by C1-2 alkylene groups.
According to a further embodiment, acridine derivatives of the formula (1) are provided in which R, R1, R2, R3, X, Z, P, Q, n and m have the meanings given above and R4 is 3,5-dimethoxyphenyl.
According to a further embodiment, acridine derivatives of the formula (1) are provided in which R4 has the meanings given above, R, R1, R2, R3 each are a hydrogen atom, Z is an oxygen atom, and X is a nitrogen atom, P and Q each are two hydrogen atoms (i.e. xe2x80x94CH2xe2x80x94), m is zero and n is the integer 2.
According to a further embodiment, acridine derivatives of the formula (1) are provided in which R, R1, R2 and R3 each are a hydrogen atom, Z is an oxygen atom, and X is a nitrogen atom, P and Q each are two hydrogen atoms (i.e. xe2x80x94CH2xe2x80x94), m is zero, n is 2, and R4 is a 3,5-dimethoxyphenyl radical.
According to a yet further feature of the present invention, a process is provided for preparing acridine derivatives of formula (1) by reacting an acridine carboxylic acid of the formula (2) in which R, R1, R2, R3 have the meanings given above, Z is an oxygen or sulfur atom, and Y is a leaving group such as halogen, hydroxyl, C1-6 alkoxy, suitably methoxy or ethoxy, xe2x80x94O-tosyl, xe2x80x94O-mesyl or imidazolyl, 
with an amine of the formula (3) in which R4, P, Q, X, m and n are as defined above, in the optional presence of diluents and auxiliaries, to form the desired acridine derivatives.
Synthesis Route
The compounds of the formula 1 can be obtained according to reaction scheme 1: 
The starting materials of formulae (2) and (3) are either commercially available or can be prepared by procedures known per se. The starting materials (2) and (3) are useful intermediates for preparing the acridine derivatives of the formula (1) according to the invention.
The solvents and auxiliaries that can be optionally used, and the reaction parameters to be used, such as reaction temperature and reaction time, are known to the person skilled in the art owing to his expert knowledge.
The acridine derivatives of the formula (1) according to the present invention are suitable as medicaments, in particular as antitumor agents, for treating mammals, in particular man, but also domestic animals such as horses, cattle, dogs, cats, rabbits, sheep, poultry and the like.
According to a further feature of the present invention, a method is provided for controlling tumors in mammals, in particular man, by administering at least one acridine derivative of formula (1) to a mammal patient an amount effective for the treatment of the tumor. The therapeutically effective dose of the acridine derivative according to the invention in question which is to be administered for the treatment depends inter alia on the nature and the stage of the oncosis, the age and the sex of the patient, the type of administration and the duration of the treatment. Administration can take place orally, rectally, buccally (for example sublingually), parenterally (for example subcutaneously, intramuscularly, intradermally or intravenously), topically or transdermally.
According to a further feature of the present invention, medicaments are provided for the treatment of tumors, which comprise, as active ingredient, at least one acridine derivative of formula (1), or a pharmaceutically acceptable salt thereof, suitably together with conventional pharmaceutically acceptable auxiliaries, additives and carriers. These can be solid, semisolid, liquid or aerosol preparations. Suitable solid preparations include, for example, capsules, powders, granules, tablets. Suitable semisolid preparations include, for example, ointments, creams, gels, pastes, suspensions, oil-in-water and water-in-oil emulsions. Suitable liquid preparations include, for example, sterile aqueous preparations for parenteral administration which are isotonic with the blood of the patient.
The invention is further illustrated in more detail by the following example without being restricted to the example.
8 g (35.84 mmol) of acridine-9-carboxylic acid were charged to 300 ml of DMF with stirring. 5.79 g (57.34 mmol) of N-methylmorpholine, then a solution of 24.24 g (46.59 mmol) of Py-BOP (1-benzotriazolyltripyrrolidinophosphonium hexafluorophosphate) and 7.96 g (35.81 mmol) of 1-(3,5-dimethoxyphenyl)piperazine in 50 ml of DMF were added successively to the mixture with further stirring. The mixture was stirred at room temperature for 12 hours, the DMF was distilled off under reduced pressure and the residue was purified on a silica gel column (Kieselgel 60, from Merck AG, Darmstadt) using the mobile phase dichloromethane/methanol/ (95:5 v/v).
Yield: 12.9 (84.2% of theoretical) m.p.: 172-175xc2x0 C.
1. Antiproliferative Action in Various Tumor Cell Lines
In a proliferation test, the antiproliferative activity of the substance D-43411 was examined using established tumor cell lines. The Cellular Dehydrogenation activity is determined in the test, which enables determination of the vitality of the cell and, indirectly, the cell count. The cell lines used are the human cervical carcinoma cell lines KB/HeLa (ATCC/CCL17), the murine lymphocyte leukemia L1210 (ATCC CCL-219), the human breast adenocarcinoma line MCF7/ATCC HTB22) and the ovary adenocarcinoma line SKOV-3 (ATCC HTB77). These are established cell lines which are very well characterized and were obtained from ATCC and cultured.
The results shown in Table 1 demonstrate the highly potent antiproliferative action of D-43411 in the cell lines SKOV-3, L-1210 and HeLa/KB. Due to the particularly slow growth of the MCF7 line, the effect of D-43411 in the test period of 48 h is only small (18% inhibition at 3.16 mg/ml; thus stated as  greater than 3.16).
2. Method
XTT Test for Cellular Dehydrogenase Activity
The adherently growing tumor cell lines HeLa/KB, SKOV-3 and MCF7 and the L1210 leukemia line, which grows in suspension, were cultivated under standard conditions in an incubator with gas inlet at 37xc2x0 C., 5% CO2 and 95% atmospheric humidity. On Test Day 1, the adherent cells are detached using trypsine/EDTA and pelleted by centrifugation. The cell pellet is then resuspended in RPMI culture medium at the appropriate cell count and transferred to a 96-well microtitre plate. The plates are then overnight cultivated in the incubator with gas inlet. The test substances are made up as stock solutions in DMSO and, on Test Day 2, diluted with culture medium to the desired concentrations. The substances in the culture medium are then added to the cells and incubated in the incubator with gas inlet for 45 h. Cells which have not been treated with test substance serve as control.
1 mg/ml of XTT (sodium 3xe2x80x2-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzenesulfonic acid) is dissolved for the XTT assay in RPMI-1640 medium without Phenol Red. Additionally, a 0.383 mg/ml solution is prepared of PMS (N-methyldibenzopyrazine methyl sulfate) in phosphate-buffered saline (PBS). On Test Day 4, 75 ml/well of the XTT-PMS mixture are pipetted onto the cell plates, which by now have been incubated with the test substances for 45 hours. To this end, the XTT solution is mixed with the PMS solution in a ratio of 50:1 (v/v) shortly before use. The cell plates are then incubated in the incubator with gas inlet for a further 3 hours, and the optical density (OD490nm) is determined in a photometer.
Using the OD490nm obtained, the inhibition is calculated in percent relative to the control. The antiproliferative activity is estimated using regression analysis.